/*
 * controller.js: model-view-controller core
 * authors: Adam Cath (acath) and Dave Pacheco (dap)
 *		(both email addresses @cs.brown.edu)
 *
 * Copyright 2006 by the Mocha team. All rights reserved.
 *
 * Email authors for permission to use. With enough (any?) demand, we might
 * release this under a BSD license.
 */

/*
 * The model view controller is an architecture for designing programs with user
 * interfaces. Look it up for more information.
 */

/*
 * Data model module.
 * The data model is primarily responsible for persistence of the cart data 
 * (via a browser cookie).
 */

function Model() {
	this.courses = new Hashtable();       
}

Model.prototype.getCourses = function () {
	return this.courses.values();
}

Model.prototype.addCourses = function (courses) {
        for (var ii in courses) {
                this.courses.put(courses[ii].getID(), courses[ii]);
        }
}

Model.prototype.removeCourse = function (id) {
	this.courses.remove(id);
}

Model.prototype.clear = function () {
	this.courses = new Hashtable();
}


/*
 * Course layout (all Strings unless mentioned)
 *	number:		    course number (including section suffix)
 *      uid:                Identifies a particular section in a particular semeseter
 *      courseRegistrationNumber: Banner CRN (students use this to register)
 *	semester:	    Mocha semester id
 *      semesterText:	    text to desplay for the semester (e.g. "F 06")
 *	title:		    course title
 *	displayTime:	    time as it should be displayed (full time string)
 *	shortDisplayTime:   hour of the course (e.g., "H"), or "..."
 *	realTime:	    time in the representation "X/Y/Z", where X is 
 *				the day (0-4 representing Mon-Fri), Y is the 
 *				starting time, and Z is the ending time (both 
 *				in minutes-past-midnight).
 *	examInfo:	    exam info string
 *	professor:	    name of the professor
 *      searchNumber:	    what we should search for to get the link for this course
 *      books:              array of books for this course. See layout below
 *	color:		    not initialized--use a coloriterator
 */
function Course(initializer) {
    for(var key in initializer) {
        this[key] = initializer[key]; 
    }
}
Course.prototype.getID = function() { 
    return this.uid;
}


/*
 * Controller module.
 * The controller is responsible for dispatching model changes to the views and
 * modifying the model on behalf of the views.
 */

var COLORS = [
	/* lighter colors (stand out better against red conflicts) */
	"#FF9999",	"#FFFF66",	"#CCFF99",	"#33FF99",	"#99FFCC",
	"#99FFFF",	"#99CCFF",	"#CCCCFF",	"#CC99FF",	"#FF99FF"
];

var COOKIE_NAME="MochaCart";
var COOKIE_VERSION="2.5";
var SEMESTER_COOKIE_NAME = "MochaSemester";

/*
 * The Controller is basically used as a singleton, but uses the object-oriented
 * model for consistency.
 */
var controller; /* used only for debugging. */
function Controller() {
        controller = this;
	this.model = new Model();
	
	var smallCalendar = document.getElementById('SmallScheduleBody');
	var bigCalendar = document.getElementById('BigScheduleBody');
	var smallAgenda = document.getElementById('SmallAgenda');
	var bigAgenda = document.getElementById('BigAgenda');
	var examTable = document.getElementById('ExamTable');
        var bookTable = document.getElementById('BookTable');
        var smallSelector = document.getElementById('SmallSemesterSelector');
        var bigSelector = document.getElementById('BigSemesterSelector');
        var icsLink = document.getElementById('DownloadIcsLink');
        
        var sem = this.currentSemester = getCookie(SEMESTER_COOKIE_NAME);
	
	this.views = [new ButtonView()];
        if (smallSelector)
                this.views.push(new SelectorView(smallSelector, sem, 
                        document.getElementById('ExtraCartStuff')));
        if (bigSelector)
                this.views.push(new SelectorView(bigSelector, sem));
	if (smallCalendar)
		this.views.push(new CalView(smallCalendar, false, sem));
	if (bigCalendar)
		this.views.push(new CalView(bigCalendar, true, sem));
	if (smallAgenda)
		this.views.push(new CourseTableView(CTV_SMALL_AGENDA_COLS, smallAgenda, sem));
	if (bigAgenda)
		this.views.push(new CourseTableView(CTV_BIG_AGENDA_COLS, bigAgenda, sem));
	if (examTable)
		this.views.push(new CourseTableView(CTV_EXAM_COLS, examTable, sem));
	if (bookTable)
		this.views.push(new BookTableView(bookTable, sem, true));
        if (icsLink)
                this.views.push(new IcsLinkView(icsLink, sem));
		
        /*
         * We have a colorIterator for each semester now.
         */
        var getColorIterator = function() { return new CircularIterator(COLORS); }
        this.colorIterators = new DefaultHashtable(getColorIterator);
        
        
	/* Ugh. This is the only way I know to generate a proper closure in JS. */
	var rerenderer_generator = function (obj) {
		return function (_) {
                        if (!obj.ignoreResizeEvents)
                                obj.rerender();
		};
	}
	
        this.ignoreResizeEvents = false;
	Util_addEvent(window, 'resize', rerenderer_generator(this));
}

/*
 * Calls rerender on each of the views.
 */
Controller.prototype.rerender = function () {
        for (var ii = 0; ii < this.views.length; ++ii) {
                this.views[ii].rerender();
        }
}

/*
 * Add courses to the model and views, but don't update persistant storage
 * (the cookie). This is used for initialization and refresh().
 *
 * @param courses An array of Objects with all the properties of a course;
 *                they don't actually have to be of type Course.
 */
Controller.prototype.addCourses = function(courses) {
	/* Assign colors to each course */
        for (var ii in courses) {
                var course = courses[ii] = new Course(courses[ii]);
                course.color = this.colorIterators.get(course.semester).next()                          

                if (!this.currentSemester) {
                        this.changeSemester(course.semesterText)
                }
        }
        
        this.model.addCourses(courses);
                
	for (var ii = 0; ii < this.views.length; ++ii) {
		this.views[ii].addCourses(courses);
	}
}

/*
 * Add courses to the cart and update persistant storage.
 * @param courses An array of Objects with all the properties of a course;
 *                they don't actually have to be of type Course.
 */
Controller.prototype.addCoursesAndSave = function(courses) {
        if (courses.length > 0) {
                this.changeSemester(courses[0].semesterText);
                this.addCourses(courses);

                var cookieCourseIDs = this.getCoursesInCookie();
                var newCourseIDs = Util_map(function (c) { 
                        return (new Course(c)).getID() }, courses);

                this.setCoursesInCookie(Util_setUnion(cookieCourseIDs, 
                                                      newCourseIDs));
        }
        this.refresh();
}

/*
 * Removes a course from the cart by ID, but do not remove it from persistant
 * storage (the cookie). This is used by refresh().
 *
 * @param id of course to remove
 */
Controller.prototype.removeCourse = function (id) {
	this.model.removeCourse(id);
	for (var ii = 0; ii < this.views.length; ++ii) {
		this.views[ii].removeCourse(id);
	}
}

/*
 * Remove a course to the cart and update persistant storage.
 *
 * @param id of course to remove 
 */
Controller.prototype.removeCourseAndSave = function(id) {
	this.removeCourse(id);
        this.setCoursesInCookie(Util_setDifference(this.getCoursesInCookie(), 
                                                   [id]));
        this.refresh();
}

Controller.prototype.clearCart = function (doConfirm) {
        if (!doConfirm || 
            confirm("Are you sure you want to clear your cart?"
                  + " This removes all courses from all semesters.")) {
                this.setCoursesInCookie([]);
                this.model.clear();
                for (var ii = 0; ii < this.views.length; ++ii) {
                        this.views[ii].clear();
                }
        }
}

Controller.prototype.addView = function (view) {
	this.views.push(view);
	var list = this.model.getCourses();
	for (var ii = 0; ii < list.length; ++ii) {
		view.addCourse(list[ii]);
	}
}

Controller.prototype.changeSemester = function (semText) {
        this.currentSemester = semText;
        for (var ii = 0; ii < this.views.length; ++ii) {
                this.views[ii].changeSemester(this.currentSemester);
        }
        setCookie(SEMESTER_COOKIE_NAME, semText);
}

/*
 * Reads the cookie. If there are any courses in the Model that aren't in the
 * cookie, calls removeCourse() on them. If there are any courses in the cookie
 * that aren't in the Model, makes an AJAX request to get the course data and
 * calls addCourses().
 */
Controller.prototype.refresh = function () {
	var cookieCourseIDs = this.getCoursesInCookie();
	var currentCourseIDs = Util_map(function (c) { return c.getID() },
		this.model.getCourses());
	
	var addedCourseIDs =   Util_setDifference(cookieCourseIDs, currentCourseIDs);
	var removedCourseIDs = Util_setDifference(currentCourseIDs, cookieCourseIDs);
        
        if (addedCourseIDs.length > 0) {
                var oldThis = this;
                var request = '/mocha/dataService/GetCourseData?courseIDs=["' + 
                        addedCourseIDs.join('","') + '"]';
                ajaxRequest(request,
                        function (courseDataJSON) {
                            oldThis.addCourses(eval(courseDataJSON));
                        });
        }
        
	for (var ii in removedCourseIDs) {
                this.removeCourse(removedCourseIDs[ii]);
	}
}

Controller.prototype.getCoursesInCookie = function() {
    var cookieText = getCookie(COOKIE_NAME);
    if (cookieText == null)
        return [];
    var parts = cookieText.split("/");
    //var version = parts[0].split("-")[1];
    var uidList = parts[1];
    return (cookieText != null) ? 
                Util_filter(function (x) { return x.length > 0 },
                            uidList.split(".")) : 
                [];
}

Controller.prototype.setCoursesInCookie = function(courseIDs) {
    setCookie(COOKIE_NAME, "version-" + COOKIE_VERSION + "/" + courseIDs.join("."));
}

/*
 * We need a way of turning off the resize events because IE sucks so much.
 * In particular, it appears to fire off window resize events while we're not
 * resizing the window (in fact, when we're READing the offsetLeft property
 * of an object)
 */
Controller.prototype.setIgnoreResizeEvents = function (doIgnore) {
        this.ignoreResizeEvents = doIgnore;
}